EL CAJON  The parents of a 4-month-old boy who died over the weekend after being left unattended in El Cajon for several hours in a car with the windows rolled up have bailed out of jail, authorities said Monday.

The infant was found unresponsive in his car seat about 1:30 p.m. Saturday at the Bella Vista Apartments on North Mollison Avenue, police said. He had been in the car since the night before.

The cause of Giovanni Soto’s death is pending further investigation, but an autopsy has been completed, the Medical Examiner’s Office said Monday.

The baby’s parents were taken into custody about 9:45 p.m. Saturday at the El Cajon police station, where they and the infant’s aunt and uncle, with whom the couple live, were being interviewed by investigators, police Lt. Frank La Haye said Monday.

On Sunday, Israel Soto, 30, was released from San Diego Central Jail at 7:34 p.m., and Jessica Quezada, 22, left the Las Colinas Detention Facility in Santee at 7:49 p.m., sheriff’s officials said. Each was released on $100,000 bail.

It’s unclear whether either returned to the apartment after being released from jail.

On Monday afternoon, a makeshift memorial of stuffed animals, candles and a few coloring book pages blocked the front door, growing larger since its start on Sunday.

Next-door neighbor Emmanuel Navarro, 34, said family had moved in a few weeks ago.

Soto and Quezada were arrested on suspicion of willful cruelty to a child resulting in injury or death. Quezada was also arrested on a charge of possession of a controlled substance.

The mother told officers that she and Soto had gone for a shopping trip Friday night and that she then stayed up late cleaning when they returned home, La Haye said.

When family members awoke the next day and realized the Giovanni was missing, they began to search for him. It was the uncle who discovered the infant in the gray Chevrolet Impala sedan and called police, La Haye said.

The car, which had Nevada license plates, was a rental car, La Haye said. No neighbors reported hearing the baby crying, he said.

An El Cajon police officer performed CPR on Giovanni until paramedics arrived. The baby was taken to Sharp Grossmont Hospital in La Mesa, where he died.

According to the National Weather Service, the temperature in El Cajon on Saturday afternoon was 81 degrees.

Quezada’s three other children, ages 1, 2 and 3, were taken into custody by county Child Protective Services. The first court appearance for her and Soto in connection with the baby’s death is Aug. 6.

Court records in San Diego show that Soto and Quezada pleaded guilty in 2009 for passing $5,300 worth of bad checks. They were each put on probation for three years.

In addition, Israel Soto pleaded guilty in 2006 to a charge of theft from an elderly or dependent adult. The charge was reduced to a misdemeanor on the condition he pay restitution of $1,822 to the victim. He was also placed on three years’ probation. It’s not clear from the court records if he paid back the money.